This invention addresses the severe need for new classes of antibacterial antibiotics for treatment of bacterial infections, and, especially infections arising from bacteria which have developed resistance to conventional antibiotics, such as methicillin-resistant infections of Staphylococcus aureus (MRSA), and bacterial species presenting significant health concerns due to their morbidity and mortality in epidemics, such as Francisella tularensis and Bacillus anthracis. 
Antibiotic resistance is a particularly critical health concern and has increased dramatically over the past two decades. Antibiotic resistance refers to the ability of a microorganism to avoid the harmful effects of an antibiotic by destroying the antibiotic, transporting it out of the cell, or undergoing changes that block its effects. Frequent exposure of a microorganism to an antibiotic provides conditions favorable to the evolution of antibiotic resistance.
MRSA is a type of Staphylococcus aureus resistant to certain antibiotics including methicillin and the more common antibiotics such as oxacillin, penicillin, and amoxicillin. MRSA incidence is on the rise in the U.S. and it has now become recognized as a major community-acquired pathogen.
This invention addresses the severe need for new classes of antibacterial antibiotics for treatment of methicillin-resistant infections of Staphylococcus aureus (MRSA) which is of epidemic concern due to their lethality and difficulty in treating in hospitals and in the open community.